"Blue seems to have been highly esteemed since far back in antiquity as
a beneficent color, denoting immortality, eternity, chastity, and fidelity, and
pale blue representing prudence and probity. Exodus 28:31 states "thou shall
make the robe of the ephod all of blue, " and Esther 1:6 states "where
were white green and blue hangings, fastened with cords of fine linen and purple."
The people were directed to wear a blue ribbon above the fringe of their garments,
and one of the veils of the Tabernacle was blue. The same color is supposed to
have been honored among the Druids. The Egyptians represented their principal
god, Amun, as colored blue. Jeremiah 10:9 indicates that the Babylonians
colored their idols blue as being an appropriate color for the gods. In Medieval
times, Christians regarded blue as symbolic of immortality, of perfection, of
hope, and of fidelity."

"It has never been discovered how or when blue became the most characteristic
color of Craft Masonry, but the most probable explanation is the simple analogy
to the blue dome of heaven, the clouded canopy, or star-decked firmament. In Masonry,
blue indicates universal brotherhood and instructs us that those virtues should
be as extensive as the blue arch of heaven itself."